2, 2-dialkylcyclopropanemethylamines



United States Patent ()1 ice 3,156,722 Patented Nov. 10, 1964 This invention relates to new cyclopropane derivatives and, more particularly, to alkylcyclopropzanemethylamine and alklcyclop-ropanemethylcarbamic acid esters, and to methods for their preparation.

The compounds of this invention have the following eneral formula R1 ofig wherein R is hydrogen or lower alk-yl, R is lower alkyl, and R is hydrogen, lower alkyl or carbo(lower alkoxy) [COO(lower alkyl)], and include non-toxic acid-addition salts of those compounds wherein R is hydrogen or lower alkyl.

Those compounds of this invention, wherein R is hydrogen or lower :alkyl, possess vasooonstrictor properties and thus may be used as nasal decongestants. For such purpose the compounds are administered topically in the form of nasal sprays or drops for treatment of congestion of mucous tissues (mg, in hay fever and sinusitus). Those compounds of this invention, wherein R is carboflower alkoxy) possess central nervous system depressant activity and thus may be used as anticonvulsants or as sedatives. For such purposes the compounds may be administered perorally (e.g., in capsule, tablet or elixir form).

The amines of the present invention, wherein R is hydrogen, can :be prepared by the reduction of the corresponding nitriles employing a hydrogenating agent, such as lithium aluminum hydride. Those compounds of this invention, wherein R is lower alkyl, are prepared from the primary amines by treatment with an acylating agent, such a formic acid; a lower alloanoic :anhydride (e.g., acetic anhydride); and a lower alkanoyl halide (e.g. propionyl chloride and hexanoyl chloride) and then reducing the resulting amide with a reducing agent such as lithium aluminum hydride. The carb-amic acid esters of this invention can be prepared by reacting the primary amines (R is hydrogen) with a chloroformate, such as a lower alk-yl chloroformate eg. methyl and ethyl chloroformate).

To prepare the acid-addition salts, the amine (R is hydrogen or lower :alkyl) is reacted in the usual manner with the desired acid. The preferred acids are those which form non-toxic salts and include inorganic acids, such as the hydrohalic acids (e.'g., hydrochloric and hydrobromic acid), sulfuric acid, nitric acid and phosphoric acid, and organic acids, such as citric, tartaric and acetic acid.

Those nitriles utilizable as starting materials in the processes of this invention which are new compounds can be prepared from the corresponding 2-R, 2-R -1,3-propanediols by reacting the latter with p-toluenesulfonyl chloride to yield the corresponding p-toluenesulfonic acid diesters, which are then reacted with potassium cyanide to give the corresponding Z-R,Z-R -cyclopropanecarbonitrile. Among the suitable propanediols may be mentioned 2- (lower alkyD-l,3-propanediols, such as 2-methyll,3-propanediol, Z-ethyl-L3-propanediol, Z-n-propyl-LB-pnopanediol, Z-isopropyl-1,3-propanediol, 2-n-butyl-l,3-propanediol and Z-n-hexyl-l,3-propanedi-ol; and 2,2-di-(lower alkyl)-l,3-.propanediols, such as 2,2-dimethyl-l,3-propanediol, Z-methyl-Z-ethyl-l,3-propanediol-2,2-diethyl-1,3pro panediol, 2-methyl-2-propyl1,3propanediol, 2-ethyl-2-nbutyl-1, 3-propanediol and 2-methyl-2-n-hexy1-1,3-propanediol.

The new nitrile starting materials can be prepared as detailed in the following examples leading to the formation of 2-methyl-2-propylcyclopropanecanb onitrile:

EXAMPLE A p-Toluenesulfonic Acid, Diester With Z-Methyl-Z-Propyl- 1 ,3 -Pr0pdnedi0l A solution of 545. grams of p-toluenesulfonyl chloride in 1200 ml. of pyridine is cooled to 0, and grams of Z-methyl-Z-n-propyl-l,3-propanediol in 200 ml. of pyridine is added dropwise with vigorous stirring. The reaction mixture is cooled in an ice bath during the addition, stirred for an additional two hours and then is allowed to warm to room temperature during the next twenty hours. The reaction mixture is then poured into two liters of ice and water. The precipitated solid is filtered, washed with water, dilute sulfuric acid, dilute aqueous sodium carbonate and again with water. The product melts at about 66-68 C. and is sufficiently pure for use in Example B. Recrystallization from ethyl acetate and pentane gives the pure product, MJP. about 6870 C.

EXAMPLE B 2-MethyZ-Z-n-Propylcyclopropanecarbonitrile A mixture of 660 grams of p toluenesulfonic acid, diester with 2-.methyl-Z-n-propyl-l,3-propanediol and 292.5 grams of potassium cyanidein 4.5 liters of ethylene glycol is heated and allowed to distill slowly until the temperature of the vapor distilling is C. The top phase of the distillate is separated and the lower phase is extracted three times with n pentane. The pentane extracts are then combined with the upper phase and washed three times with water. The pentane is removed by distillation and the residue fractionally distilled to obtain the product, boiling at about 81-83 at 8 mm.

The following examples illustrate the invention (all temperatures given are in degrees Centigrade) EXAMPLE 1 2,2-Diethylcyclopropanemefliylamine Hydrochloride 14.8 g. of lithium aluminum hydride is added to 700 ml. of absolute ether and the suspension stirred at reflux for one-half hour. The suspension is cooled and a solution of 33.3 g. of 2,2-diethylcycloprop anecarbonitrile in 50ml. of absolute other is added dropwise with stirring. The mixture is stirred and refluxed for one hour, then cooled, and 32.4 g. of water added with caution. The reaction mixture is then cooled and filtered. The filter cake is washed with 250 ml. of ether and the combined filtrate and washes are dried with potassium hydroxide pellets.

The dried ether solution is filtered and 62.5 ml. of a 4.02 N solution of hydrogen chloride in ether is added. The white needles which form are washed with dry ether. The dry material weighs about 3 3.4 g.; M.P. about 220- 222 (doc) and upon one recrystallization from acetonitr-ile gives about 28.0 g. 2,2-diethylcyclopropanernethylamine hydrochloride as broad white needles; M.P. about 225-225 .5

EXAMPLE 2 N-(2,2-Diethylcyclopropylmethyl)Carlzamic Acid, Ethyl Ester 23.0 g. of 2,2-diethylcyclopropanemethylamine hydrochloride is added to a solution of 11.2 g. of sodium hydroxide in 250 ml. of water cooled in an ice-bath. 15.4 g. of ethyl chloroformate is added to the stirred mixture at such a rate that the temperature does not rise above 5". The reaction mixture is allowed to stir until the pH has reached a constant value of 8.4. It is then extracted with 3 500 ml. of ether and the ether layer washed with 50 ml. portions of water, 1% hydrochloric acid, and a saturated sodium bicarbonate solution and dried over anhydrous magnesium sulfate.

Concentration of the ether yields about 20.0 g. of a colorless liquid; 11 1.4553 which, upon distillation, gives about 14.4 g. of N-(2,2-diethylcyclopropylmethyl)carbamic acid, ethyl ester; 11 1.4550; B.P. about 92- 97/0.25 mm.

Analysis.-Calcd. for C H NO C, 66.29; H, 10.62; N, 7.03. Found: C, 66.59; H, 10.68; N, 7.02.

EXAMPLE 3 2-Methyl-2-n-Propylcyclopropanemethylamine Hydrochloride 17.8 g. of lithium aluminum hydride is stirred and refluxed with 900 ml. of absolute ether for 0.5 hour. When cool, a solution of 40.0 g. of Z-methyl-Z-n-propylcyclopropylcarbonitrile in 100 ml. of absolute ether is added to the stirred suspension at a rate suflicient to maintain reflux. The reaction mixture is stirred and refluxed for one hour and allowed to cool. 37.8 g. of water is slowly added and the suspension is stirred for an additional hour. The mixture is filtered and the filter cake washed with absolute ether. The combined filtrate and washes are dried for one hour over potassium hydroxide pellets and filtered. 86 ml. of a 4.2 N ethereal hydrogen chloride solution is added to the filtrate. After cooling, the white plates formed are collected by filtration, washed with absolute ether, and allowed to dry in the air. In this manner, about 40.4 g. of 2-methyl-2-n-propylcyclopropanemethylamine hydrochloride; M.P. about 169.0- 170.5", is obtained.

EXAMPLE 4 N 2-M ethyl-Z-n-Propylcyclopropylmethyl Carbamic Acid, Ethyl Ester 32.0 g. of 2-methyl-2-n-propylcyclopropanernethylamine hydrochloride is dissolved in a solution of 16.0 g. of sodium hydroxide in 400 ml. of water. The solution is cooled in an ice bath and during stirring 23.4 g. of ethyl chloroformate is added at such a rate that the temperature does not exceed 10. Stirring is continued for one hour after the addition is completed and the reaction mixture is then extracted with a 500 ml. and a 250 ml. portion of ether. The combined extracts are washed with 100 ml. portions of water, 1% aqueous hydrochloric acid, saturated aqueous sodium bicarbonate, and water again and then dried with anhydrous magnesium sulfate.

Evaporation of the ether gives about 38.5 g. of a yellowish liquid. Fractionation with a Vigreaux column gives about 30.4 g. of N-(2-methyl-2-n-propylcyclopropylmethyl)carbamic acid, ethyl ester; B.P. 99102/0.5 mm.; 11 1.4512.

EXAMPLE 5 N -M ethyl-2,2-Diethylcyclopropanemethylam inc (a) Preparation of N (2,2-diethylcyclopropanemethyl)- formamide: To twenty-five grams of formic acid (98 100%) there is added dropwise, with vigorous stirring, nineteen grams of 2,Z-diethylcyclopropanemethyl-amine and the reaction mixture is heated under reflux for 8 hours. The excess acid is then removed by distillation under reduced pressure and the cooled residue is diluted with 100 m1. of water. The aqueous suspension is treated with solid potassium carbonate and the organic material extracted with chloroform. The chloroform solution is washed with dilute hydrochloride acid, saturated sodium chloride solution and then dried over anhydrous magnesium sulfate. The desired N-(2,2-diethylcyclopropanemethyDformamide is obtained by concentration of the chloroform first at atmospheric pressure and finally under reduced pressure.

(b) Preparation of N-methyl-2,2-diethylcyclopropanemethylamine: To a suspension of 3.8 grams of lithium aluminum hydride in 300 ml. of anhydrous ether, there is added dropwise, with vigorous stirring, a solution of 8 grams of N(2,Z-diethylcyclopropanemethyl)formamide in ml. of anhydrous ether. The reaction mixture is refluxed for three hours after the addition is complete. It is then cooled and treated dropwise with 10 ml. of water. The reaction mixture is then filtered, the solid washed with ether, and filtrate and washings combined. The aqueous layer is removed and the ether solution dried with anhydrous potassium carbonate. The residue from the concentration of the ether solution is fractionally distilled under reduced pressure to yield the desired n-methyl- 2,2-diethylcyclopropanernethylamine.

This invention may be variously otherwise embodied within the scope of the appended claims.

What is claimed is:

1. A compound selected from the group consisting of those of the formula R1 CH2 wherein R is a member selected from the group consisting of hydrogen and lower alkyl; R is lower alkyl; and R is a member selected from the group consisting of hydrogen and lower alkyl, and non-toxic acid-addition salts thereof.

2. A non-toxic and acid-addition salt of 2,2-di(lower alkyl) cyclopropanemethylamine.

3. 2,2-diethylcyclopropanemethylamine hydrochloride.

4. 2-methyl-2-propylcyclopropanemethylamine hydrochloride.

5. N-(lower alkyl)-2,2-di(lower a1kyl)cyclopropanernethylamine.

6. N-methyl-2,Z-diethylcyclopropanemethylamine.

References Cited in the file of this patent UNITED STATES PATENTS 1,670,990 Rupe May 22, 1928 2,416,068 Schweitzer Feb. 18, 1947 2,483,693 Dobratz Oct. 4, 1949 2,532,561 Langkammerer Dec. 5, 1950 2,534,088 Webb Dec. 12, 1950 2,576,311 Schlesinger et al Nov. 27, 1951 2,782,218 Drysdale Feb. 19, 1957 2,816,928 Smiley Dec. 17, 1957 2,945,063 Quinn et a1 July 12, 1960 3,017,395 Elam et al. Jan. 16, 1962 FOREIGN PATENTS 544,890 Germany Feb. 23, 1932 OTHER REFERENCES Demjanow et al.: Ber. Deut. Chem, vol. 55, 2718- 2730 (1922).

Demjanow et al.: Ber. Deut. Chem., vol. 56, pp. 2208- 2212 (1923).

Shuikina, C. A.: vol. 31, p. 5332 (1937).

Braker et al.; J.A.C.S., vol. 69, pp. 867-869 (1947), 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF THOSE OF THE FORMULA 